Deck 22: Waiting Lines

Question 1

Waiting lines cannot develop if the time to process a customer is constant.

Answer 1

False

Question 2

The four elements common to all waiting-line situations are a customer population,a waiting line of customers,the service facility,and a priority rule.

Answer 2

True

Question 3

The best example of a finite customer population is

A) the car-buying public of an automotive manufacturer.
B) the constituents in a precinct lining up to vote.
C) the e-mail messages arriving at a major ISP mail server.
D) the members of the Management department at your university waiting to speak to the Dean about their department chairman.

Answer 3

D

Question 4

The number of customers in queue and being served also relates to service efficiency and capacity.

Question 5

A phase represents a single step in providing a service.

Question 6

Management,servers,and customers would all be happy if,in a single-server situation,the parameter ? is much greater than

Question 7

Long lines always mean long waiting times.

Question 8

A bank that dedicates one window for commercial account customers and one window for personal account channel has two channels.

Question 9

Which of the following is LEAST likely to benefit from waiting line analysis?

A) Capacity planning
B) Inventory management
C) Budget planning
D) Scheduling

Question 10

Pre-emptive discipline is a rule that allows a customer of lower priority to interrupt the service of another customer.

Question 11

In a single-channel,single-phase system,all operations demanded by a customer can be performed by a single workstation.

Question 12

The mean of the Poisson distribution is equal to its standard deviation.

Question 13

Short queue lengths typically mean not enough capacity.

Question 14

If the service system generates customers according to a Poisson distribution,the exponential distribution describes the probability that the next customer will arrive in the next T time periods.

Question 15

Ed Deadbeat races to the Bursar's Office on the first day of class and notes that the line is four students long.Ed figures that the wait will be at least ten minutes and,having better uses of his time,he decides to proceed to the next item on his to-do list.Ed's behaviour is best described as

A) reneging.
B) balking.
C) blocking.
D) queuing.

Question 16

The distinction between an infinite customer population and a finite customer population is

A) whether the potential number of customers is appreciably affected by the number of customers already in the system.
B) whether the number of potential customers exceeds the square of the number of servers.
C) whether the number of potential customers exceeds the number of servers raised to the power of the number of channels.
D) if the number of customers exceeds infinity.

Question 17

Waiting Line specifically refers one customer or item waiting for service.

Question 18

Operations time refers to a time to complete a subset of activities at a workstation.

Question 19

It is impossible for management to affect the rate of customer arrivals.

Question 20

India Sisson wants to grab a latte before heading to her marketing class,knowing that the jolt of a double tall mocha is the only thing that can possibly keep her eyes open during today's presentation on the four Ps.The barista is slower than molasses in January and India notes that the pace of the line won't permit her to grab her favorite seat in the back row of her class.She decides to risk marketing without a latte and leaves the line before getting served.India's behaviour is best described as

A) balking.
B) blocking.
C) reneging.
D) queuing.

Question 21

The owner of a desktop publishing company has seven loyal clients who periodically require his services.The owner has

A) an infinite customer population of patient customers.
B) an infinite population of impatient customers.
C) a finite customer population.
D) a finite customer population with balking customers.

Question 22

Customers are serviced at a rate of five customers per hour according to an exponential distribution.What is the probability that customer service will require fewer than 20 minutes?

A) Less than or equal to 0.75
B) Greater than 0.75 but less than or equal to 0.80
C) Greater than 0.80 but less than or equal to 0.85
D) Greater than 0.85

Question 23

Customers arrive according to a Poisson distribution.The average number of customer arrivals per hour is four.The probability that three customers will arrive in the next two hours is

A) less than or equal to 0.015.
B) greater than 0.015 but less than or equal to 0.020.
C) greater than 0.020 but less than or equal to 0.025.
D) greater than 0.025.

Question 24

With a single-server model,increasing the promotions for a service through advertising will most likely

A) increase the utilization of the server.
B) decrease the average number of customers in the service system.
C) decrease the average time a customer spends in the system.
D) increase the probability that the server will be idle.

Question 25

A super computer-accessory discount store often has customers who leave the checkout line before being served because of excessive waiting times.The store has a(n)

A) infinite customer population with balking customers.
B) infinite customer population with reneging customers.
C) finite customer population with balking customers.
D) finite customer population with reneging customers.

Question 26

A homemade-ice cream shop owner has noticed that,often,potential customers will stop outside the store,assess the wait in line,and then pass by.The shop has a(n)

A) infinite customer population with balking customers.
B) infinite customer population with reneging customers.
C) finite customer population with balking customers.
D) finite customer population with reneging customers.

Question 27

The single,multiple,and finite queuing models all assume that

A) the arrival rate exceeds the service rate.
B) the number of servers exceeds the number of customers.
C) the number of customers exceeds the number of servers.
D) the customers are patient.

Question 28

Customers arrive according to a Poisson distribution.The average number of customer arrivals per hour is three.The probability that four customers will arrive in the next two hours is

A) less than or equal to 0.10.
B) greater than 0.10 but less than or equal to 0.12.
C) greater than 0.12 but less than or equal to 0.14.
D) greater than 0.14.

Question 29

Customers are serviced at a rate of 10 customers per hour according to an exponential distribution.What is the probability that customer service will require fewer than two minutes?

A) Less than or equal to 0.25
B) Greater than 0.25 but less than or equal to 0.30
C) Greater than 0.30 but less than or equal to 0.35
D) Greater than 0.35

Question 30

Customers are serviced at a rate of four customers per hour according to an exponential distribution.What is the probability that customer service will require fewer than 30 minutes?

A) Less than or equal to 0.50
B) Greater than 0.50 but less than or equal to 0.60
C) Greater than 0.60 but less than or equal to 0.70
D) Greater than 0.70

Question 31

Customers are serviced at a rate of six customers per hour according to an exponential distribution.What is the probability that customer service will require fewer than 20 minutes?

A) Less than or equal to 0.70
B) Greater than 0.70 but less than or equal to 0.80
C) Greater than 0.80 but less than or equal to 0.90
D) Greater than 0.90

Question 32

Customers arrive according to a Poisson distribution.The average number of customer arrivals per hour is two.The probability that five customers will arrive in the next three hours is

A) less than or equal to 0.10.
B) greater than 0.10 but less than or equal to 0.12.
C) greater than 0.12 but less than or equal to 0.14.
D) greater than 0.14.

Question 33

With a single-server model,increasing the capital-to-labor ratio will most likely

A) increase the utilization of the server.
B) have no effect on the operating characteristics because they are affected only by work-methods changes.
C) decrease the probability that there are zero customers in the system at any time.
D) decrease the average number of customers in the waiting line.

Question 34

Customers are serviced at a rate of three customers per hour according to an exponential distribution.What is the probability that customer service will require fewer than 10 minutes?

A) Less than or equal to 0.40
B) Greater than 0.40 but less than or equal to 0.45
C) Greater than 0.45 but less than or equal to 0.50
D) Greater than 0.50

Question 35

An automatic,drive-through car wash is an example of a

A) single-channel, single-phase arrangement.
B) single-channel, multiple-phase arrangement.
C) multiple-channel, single-phase arrangement.
D) multiple-channel, multiple-phase arrangement.

Question 36

A bank lobby with six teller windows,each with a separate line,is an example of a

A) single-channel, single-phase arrangement.
B) single-channel, multiple-phase arrangement.
C) multiple-channel, single-phase arrangement.
D) multiple-channel, multiple-phase arrangement.

Question 37

Customers arrive according to a Poisson distribution.The average number of customer arrivals per hour is six.The probability that four customers will arrive in the next three hours is

A) less than or equal to 0.01.
B) greater than 0.01 but less than or equal to 0.02.
C) greater than 0.02 but less than or equal to 0.03.
D) greater than 0.03.

Question 38

With a single-server model,increasing the service rate while holding all other factors constant will

A) increase the utilization of the server.
B) increase the time spent per customer.
C) decrease the probability that there are two customers in the system at any time.
D) decrease the arrival rate of customers.

Question 39

A Laundromat where there are washing machines and dryers is an example of a

A) single-channel, single-phase arrangement.
B) single-channel, multiple-phase arrangement.
C) multiple-channel, single-phase arrangement.
D) multiple-channel, multiple-phase arrangement.

Question 40

A drive-through system at a fast food restaurant where the first facility takes the order,the second takes the money,and the third provides the food is an example of

A) single-channel, single-phase arrangement.
B) single-channel, multiple-phase arrangement.
C) multiple-channel, single-phase arrangement.
D) multiple-channel, multiple-phase arrangement.

Question 41

With a single-server model,increasing the arrival rate by 10 percent and also increasing the service rate by 10 percent will result in

A) a decrease in the utilization of the server.
B) no change in the average number of customers in the service system.
C) an increase in the average number of customers in the waiting line.
D) an increase in the waiting time in line.

Question 42

A single ticket taker can tear tickets and direct movie patrons to their seats at a rate of 90 per hour. Customers arrive every minute for assistance and always wait, regardless of how long the line gets. Arrivals are governed by the Poisson distribution and service is governed by the exponential distribution.
Use the information in Scenario C.1.What is the average number of customers in line?

A) 0.33
B) 0.66
C) 1.33
D) 2.00

Question 43

Weary travelers arrive at Will Rogers International Airport, pick up their luggage, stumble to their cars, and proceed to the parking lot attendant to pay for their parking. Traveler interarrival times are exponentially distributed, as are the service times of the attendant. On average, travelers arrive every 25 seconds. The attendant can process three travelers per minute.
Use the information in Scenario C.2.What is the average number of customers in line?

A) Fewer than or equal to 1.0
B) Greater than 1.0 but fewer than or equal to 2.0
C) Greater than 2.0 but fewer than or equal to 3.0
D) Greater than 3.0

Question 44

A single ticket taker can tear tickets and direct movie patrons to their seats at a rate of 90 per hour. Customers arrive every minute for assistance and always wait, regardless of how long the line gets. Arrivals are governed by the Poisson distribution and service is governed by the exponential distribution.
Use the information in Scenario C.1.What is the average time a customer must wait in line?

A) 0.66 minutes
B) 1.33 minutes
C) 2.00 minutes
D) 3.00 minutes

Question 45

A single ticket taker can tear tickets and direct movie patrons to their seats at a rate of 90 per hour. Customers arrive every minute for assistance and always wait, regardless of how long the line gets. Arrivals are governed by the Poisson distribution and service is governed by the exponential distribution.
Use the information in Scenario C.1.What is the probability that customers with tickets arrive and the ticket taker is not helping another patron?

A) 0.011
B) 0.11
C) 0.22
D) 0.33

Question 46

With a finite-source model,increasing the arrival rate by 10 percent and also increasing the service rate by 10 percent will result in

A) an increase in the utilization of the server.
B) an increase in the average number of customers in the service system.
C) a decrease in the average time spent in the system, including service.
D) an increase in the waiting time in line.

Question 47

With a single-server model,increasing the arrival rate by 10 percent and also increasing the service rate by 10 percent will result in

A) no change in the probability that there are n customers in the system.
B) a decrease in the average waiting time in line.
C) an increase in the average time spent in the system, including service.
D) an increase in the average number of customers in the system.

Question 48

In the single-server model,

A) customers are assumed to arrive at constant intervals of time.
B) the variability of customer arrivals is most often described by a Poisson distribution.
C) the mean of the distribution of customer arrivals must be greater than the variance of customer arrivals to get meaningful results.
D) the probability of n arrivals in T time periods comes from a normal distribution.

Question 49

A single ticket taker can tear tickets and direct movie patrons to their seats at a rate of 90 per hour. Customers arrive every minute for assistance and always wait, regardless of how long the line gets. Arrivals are governed by the Poisson distribution and service is governed by the exponential distribution.
Use the information in Scenario C.1.What is the average combined time a customer waits in line and spends being seated by the ticket taker?

A) 1.00 minute
B) 1.50 minutes
C) 2.00 minutes
D) 3.00 minutes

Question 50

With a finite-source model,increasing the arrival rate by 10 percent and also increasing the service rate by 10 percent will result in

A) a decrease in the utilization of the server.
B) no change in the average number of customers in the system.
C) an increase in the average number of customers in the waiting line.
D) an increase in the waiting time in line.

Question 51

With a single-server model,increasing the arrival rate by 10 percent and also increasing the service rate by 10 percent will result in

A) an increase in the utilization of the server.
B) an increase in the average number of customers in the system.
C) a decrease in the average time spent in the system, including service.
D) an increase in the waiting-line time.

Question 52

A single ticket taker can tear tickets and direct movie patrons to their seats at a rate of 90 per hour. Customers arrive every minute for assistance and always wait, regardless of how long the line gets. Arrivals are governed by the Poisson distribution and service is governed by the exponential distribution.
Use the information in Scenario C.1.What is the average number of people waiting in line and being seated?

A) 0.66
B) 1.00
C) 2.00
D) 3.00

Question 53

In the single-server model,

A) the service time of a customer is most often described by an exponential distribution.
B) the service time depends on the number of customers in the system as long as there is at least one customer in the waiting line.
C) the mean of the service-time distribution must be as great as the target service time for a feasible solution.
D) service times are always constant to avoid large waiting lines.

Question 54

In order to have equivalent performance on average waiting time in a single server model,an increase in interarrival time must be accompanied by

A) an increase in ?.
B) an increase in the number of servers.
C) an increase in the number of channels.
D) an increase in the line length.

Question 55

With a multiple-server model,increasing the arrival rate by 10 percent and also increasing the service rate of each server by 10 percent will result in

A) a decrease in the utilization of the system.
B) no change in the average number of customers in the waiting line.
C) a decrease in the average number of customers in the waiting line.
D) an increase in the waiting time in line.

Question 56

A single ticket taker can tear tickets and direct movie patrons to their seats at a rate of 90 per hour. Customers arrive every minute for assistance and always wait, regardless of how long the line gets. Arrivals are governed by the Poisson distribution and service is governed by the exponential distribution.
Use the information in Scenario C.1.What is the utilization of the ticket taker?

A) 0.66
B) 0.55
C) 0.44
D) 0.33

Question 57

Weary travelers arrive at Will Rogers International Airport, pick up their luggage, stumble to their cars, and proceed to the parking lot attendant to pay for their parking. Traveler interarrival times are exponentially distributed, as are the service times of the attendant. On average, travelers arrive every 25 seconds. The attendant can process three travelers per minute.
Use the information in Scenario C.2.What is the average number of customers in the system?

A) Fewer than or equal to 3.0
B) Greater than 3.0 but fewer than or equal to 5.0
C) Greater than 5.0 but fewer than or equal to 7.0
D) Greater than 7.0

Question 58

Weary travelers arrive at Will Rogers International Airport, pick up their luggage, stumble to their cars, and proceed to the parking lot attendant to pay for their parking. Traveler interarrival times are exponentially distributed, as are the service times of the attendant. On average, travelers arrive every 25 seconds. The attendant can process three travelers per minute.
Use the information in Scenario C.2.How many minutes per hour is the attendant not serving customers?

A) Fewer than or equal to 13
B) Greater than 13 but fewer than or equal to 17
C) Greater than 17 but fewer than or equal to 21
D) Greater than 21

Question 59

Weary travelers arrive at Will Rogers International Airport, pick up their luggage, stumble to their cars, and proceed to the parking lot attendant to pay for their parking. Traveler interarrival times are exponentially distributed, as are the service times of the attendant. On average, travelers arrive every 25 seconds. The attendant can process three travelers per minute.
Use the information in Scenario C.2.What is the probability that a traveler will pull up to the attendant's service window without having to wait for another customer?

A) Less than or equal to 0.15
B) Greater than 0.15 but less than or equal to 0.25
C) Greater than 0.25 but less than or equal to 0.35
D) Greater than 0.35

Question 60

Weary travelers arrive at Will Rogers International Airport, pick up their luggage, stumble to their cars, and proceed to the parking lot attendant to pay for their parking. Traveler interarrival times are exponentially distributed, as are the service times of the attendant. On average, travelers arrive every 25 seconds. The attendant can process three travelers per minute.
Use the information in Scenario C.2.What is the average time a customer spends in line?

A) Less than or equal to 1.0 minute
B) Greater than 1.0 but fewer than or equal to 2.0 minutes
C) Greater than 2.0 but fewer than or equal to 3.0 minutes
D) Greater than 3.0 minutes

Question 61

The Jackson Machine Company has four cutting tools that need to be refurbished after an average of 30 hours, according to an exponential distribution. The single machine that refurbishes the tools needs 15 hours for each tool on the average, with exponential service times.
Use the information in Scenario C.6.What is the average utilization of the refurbishing machine?

A) Less than or equal to 40 percent
B) Greater than 40 percent but less than or equal to 50 percent
C) Greater than 50 percent but less than or equal to 60 percent
D) Greater than 60 percent

Question 62

Customers arrive at a ticket counter at the rate of 50 customers per hour, according to a Poisson distribution. There are three ticket agents. Customers select the first available agent from one line. Each agent can process 20 customers per hour with exponential service times.
Use the information in Scenario C.4.What is the average number of customers waiting in line for service?

A) Fewer than or equal to four
B) Greater than four but fewer than or equal to 4.5
C) Greater than 4.5 but fewer than or equal to five
D) Greater than five

Question 63

Customers arrive at a ticket counter at the rate of 50 customers per hour, according to a Poisson distribution. There are three ticket agents. Customers select the first available agent from one line. Each agent can process 20 customers per hour with exponential service times.
Use the information in Scenario C.4.What is the average utilization of the three-agent system?

A) Less than or equal to 80 percent
B) Greater than 80 percent but less than or equal to 85 percent
C) Greater than 85 percent but less than or equal to 90 percent
D) Greater than 90 percent

Question 64

Customers arrive at the one remaining full-service gas station in the country at the rate of 45 per minute and are served by the first available of three pump jockeys who can dole out gas and check oil at the rate of 20 customers per minute. Both service and interarrival times are governed by the exponential distribution. The probability that no pump jockey is busy is 0.0748.
Use the information in Scenario C.3.What is the probability that an arrival at the gas station must wait?

A) Less than or equal to 0.50
B) Greater than 0.50 but less than or equal to 0.60
C) Greater than 0.60 but less than or equal to 0.70
D) Greater than 0.70

Question 65

A trucking firm has five trucks that each requires service at an average rate of once every 50 hours, according to an exponential distribution. The firm has a mechanic who needs five hours to complete the average job with exponential service times.
Use the information in Scenario C.5.What is the average utilization of the mechanic?

A) Less than or equal to 50 percent
B) Greater than 50 percent but less than or equal to 60 percent
C) Greater than 60 percent but less than or equal to 70 percent
D) Greater than 70 percent

Question 66

A trucking firm has five trucks that each requires service at an average rate of once every 50 hours, according to an exponential distribution. The firm has a mechanic who needs five hours to complete the average job with exponential service times.
Use the information in Scenario C.5.What is the average waiting time of trucks in line?

A) Fewer than or equal to 1.5 hours
B) Greater than 1.5 hours but fewer than or equal to 1.7 hours
C) Greater than 1.7 hours but fewer than or equal to 1.9 hours
D) Greater than 1.9 hours

Question 67

Customers arrive at the one remaining full-service gas station in the country at the rate of 45 per minute and are served by the first available of three pump jockeys who can dole out gas and check oil at the rate of 20 customers per minute. Both service and interarrival times are governed by the exponential distribution. The probability that no pump jockey is busy is 0.0748.
Use the information in Scenario C.3.What is the average number of customers in the system?

A) Fewer than or equal to 3.0
B) Greater than 3.0 but fewer than or equal to 3.5
C) Greater than 3.5 but fewer than or equal to 4.0
D) Greater than 4.0

Question 68

The Jackson Machine Company has four cutting tools that need to be refurbished after an average of 30 hours, according to an exponential distribution. The single machine that refurbishes the tools needs 15 hours for each tool on the average, with exponential service times.
Use the information in Scenario C.6.What is the probability that there will be no tools in the system?

A) Less than or equal to 0.09
B) Greater than 0.09 but less than or equal to 0.13
C) Greater than 0.13 but less than or equal to 0.17
D) Greater than 0.17

Question 69

Customers arrive at the one remaining full-service gas station in the country at the rate of 45 per minute and are served by the first available of three pump jockeys who can dole out gas and check oil at the rate of 20 customers per minute. Both service and interarrival times are governed by the exponential distribution. The probability that no pump jockey is busy is 0.0748.
Use the information in Scenario C.3.What is the average time a customer spends in the system?

A) Fewer than or equal to five seconds
B) Greater than five seconds but fewer than or equal to six seconds
C) Greater than six seconds but fewer than or equal to seven seconds
D) Greater than seven seconds

Question 70

Weary travelers arrive at Will Rogers International Airport, pick up their luggage, stumble to their cars, and proceed to the parking lot attendant to pay for their parking. Traveler interarrival times are exponentially distributed, as are the service times of the attendant. On average, travelers arrive every 25 seconds. The attendant can process three travelers per minute.
Use the information in Scenario C.2.What is the average amount of time a customer spends waiting in line and being served?

A) Less than or equal to 1.0 minutes
B) Greater than 1.0 minutes but fewer than or equal to 1.50 minutes
C) Greater than 1.5 minutes but fewer than or equal to 2.0 minutes
D) Greater than 2.0 minutes

Question 71

The average lead time of a unit of product through a manufacturing station is 10 minutes.The production rate has been steady at five units per hour.The average work-in-process inventory at this station is

A) 50 units.
B) 10 units.
C) 5 units.
D) 0.83 units.

Question 72

Customers arrive at the one remaining full-service gas station in the country at the rate of 45 per minute and are served by the first available of three pump jockeys who can dole out gas and check oil at the rate of 20 customers per minute. Both service and interarrival times are governed by the exponential distribution. The probability that no pump jockey is busy is 0.0748.
Use the information in Scenario C.3.What is the average number of customers in line?

A) Fewer than or equal to 2.0
B) Greater than 2.0 but fewer than or equal to 3.0
C) Greater than 3.0 but fewer than or equal to 4.0
D) Greater than 4.0

Question 73

A trucking firm has five trucks that each requires service at an average rate of once every 50 hours, according to an exponential distribution. The firm has a mechanic who needs five hours to complete the average job with exponential service times.
Use the information in Scenario C.5.What is the average number of trucks waiting for service?

A) Fewer than or equal to 0.10
B) Greater than 0.10 but fewer than or equal to 0.14
C) Greater than 0.14 but fewer than or equal to 0.18
D) Greater than 0.18

Question 74

A trucking firm has five trucks that each requires service at an average rate of once every 50 hours, according to an exponential distribution. The firm has a mechanic who needs five hours to complete the average job with exponential service times.
Use the information in Scenario C.5.What is the average number of trucks in line waiting and being serviced?

A) Fewer than or equal to 0.30 trucks
B) Greater than 0.30 trucks but fewer than or equal to 0.40 trucks
C) Greater than 0.40 trucks but fewer than or equal to 0.50 trucks
D) Greater than 0.50 trucks

Question 75

Customers arrive at the one remaining full-service gas station in the country at the rate of 45 per minute and are served by the first available of three pump jockeys who can dole out gas and check oil at the rate of 20 customers per minute. Both service and interarrival times are governed by the exponential distribution. The probability that no pump jockey is busy is 0.0748.
Use the information in Scenario C.3.What is the utilization of the pump jockeys?

A) Less than or equal to 60 percent
B) Greater than 60 percent but less than or equal to 70 percent
C) Greater than 70 percent but less than or equal to 80 percent
D) Greater than 80 percent

Question 76

Customers arrive at a ticket counter at the rate of 50 customers per hour, according to a Poisson distribution. There are three ticket agents. Customers select the first available agent from one line. Each agent can process 20 customers per hour with exponential service times.
Use the information in Scenario C.4.What is the average time spent in the system?

A) Fewer than or equal to 6.5 minutes
B) Greater than 6.5 minutes but fewer than or equal to 7.5 minutes
C) Greater than 7.5 minutes but fewer than or equal to 8.5 minutes
D) Greater than 8.5 minutes

Question 77

Customers arrive at a ticket counter at the rate of 50 customers per hour, according to a Poisson distribution. There are three ticket agents. Customers select the first available agent from one line. Each agent can process 20 customers per hour with exponential service times.
Use the information in Scenario C.4.What is the average waiting time in line?

A) Fewer than or equal to 3.5 minutes
B) Greater than 3.5 minutes but fewer than or equal to 4.5 minutes
C) Greater than 4.5 minutes but fewer than or equal to 5.5 minutes
D) Greater than 5.5 minutes

Question 78

A trucking firm has five trucks that each requires service at an average rate of once every 50 hours, according to an exponential distribution. The firm has a mechanic who needs five hours to complete the average job with exponential service times.
Use the information in Scenario C.5.What is the probability that there will be no trucks in the system?

A) Less than or equal to 0.50
B) Greater than 0.50 but less than or equal to 0.60
C) Greater than 0.60 but less than or equal to 0.70
D) Greater than 0.70

Question 79

A trucking firm has five trucks that each requires service at an average rate of once every 50 hours, according to an exponential distribution. The firm has a mechanic who needs five hours to complete the average job with exponential service times.
Use the information in Scenario C.5.What is the average time a truck spends in the system?

A) Fewer than or equal to 6.5 hours
B) Greater than 6.5 hours but fewer than or equal to 7.0 hours
C) Greater than 7.0 hours but fewer than or equal to 7.5 hours
D) Greater than 7.5 hours

Question 80

The Jackson Machine Company has four cutting tools that need to be refurbished after an average of 30 hours, according to an exponential distribution. The single machine that refurbishes the tools needs 15 hours for each tool on the average, with exponential service times.
Use the information in Scenario C.6.What is the average waiting time of tools in line?

A) Fewer than or equal to 15 hours
B) Greater than 15 hours but fewer than or equal to 25 hours
C) Greater than 25 hours but fewer than or equal to 35 hours
D) Greater than 35 hours